Coherent phonon and charge dynamics in antimony sulfide.
Antimony Sulfide (Sb2S3) is a promising light absorbing material due to its small bandgap and large absorption coefficient in the visible region. It has recently gained much research interests as a viable material for semiconductor-sensitized solar cells (SSSCs). While there are numerous studies don...
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sg-ntu-dr.10356-536662023-02-28T23:11:46Z Coherent phonon and charge dynamics in antimony sulfide. Chong, Wee Kiang. Sum Tze Chien School of Physical and Mathematical Sciences DRNTU::Science::Physics::Optics and light Antimony Sulfide (Sb2S3) is a promising light absorbing material due to its small bandgap and large absorption coefficient in the visible region. It has recently gained much research interests as a viable material for semiconductor-sensitized solar cells (SSSCs). While there are numerous studies done to optimize the features of the Sb2S3-SSCs, the phonon and charge dynamics are not thoroughly studied. In this work, transient absorption spectroscopy (TAS) will be used to investigate this. TAS using a 400nm excitation wavelength shows coherent oscillations which were resolved to have a frequency of (1.91±0.01)THz and a small cosine phase of (-0.3±0.3)rad. The oscillations were determined to be from phonon with frequency slightly red-shifted from the AgRaman peaks, which can be attributed to a phonon softening effect. With non-resonant excitation, no oscillations are observed and therefore a displacive excitation can be attributed to the phonon generation in Sb2S3. In addition, TAS revealed two processes that decay within 10ps. One of the processes has a lifetime that resembles the laser temporal width and can be attributed to multi-probe absorption. The other process has a lifetime that decreases with increasing pump fluence and can be attributed to the electron-incoherent phonon scattering. The large scattering processes found may also indicate a possible energy loss channel for the carriers. These findings thus shed new light on the interesting quasi-particle and charge dynamics in this novel light harvesting system. Bachelor of Science in Physics 2013-06-06T08:34:17Z 2013-06-06T08:34:17Z 2013 2013 Final Year Project (FYP) http://hdl.handle.net/10356/53666 en 87 p. application/pdf |
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DRNTU::Science::Physics::Optics and light Chong, Wee Kiang. Coherent phonon and charge dynamics in antimony sulfide. |
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Antimony Sulfide (Sb2S3) is a promising light absorbing material due to its small bandgap and large absorption coefficient in the visible region. It has recently gained much research interests as a viable material for semiconductor-sensitized solar cells (SSSCs). While there are numerous studies done to optimize the features of the Sb2S3-SSCs, the phonon and charge dynamics are not thoroughly studied. In this work, transient absorption spectroscopy (TAS) will be used to investigate this.
TAS using a 400nm excitation wavelength shows coherent oscillations which were resolved to have a frequency of (1.91±0.01)THz and a small cosine phase of (-0.3±0.3)rad. The oscillations were determined to be from phonon with frequency slightly red-shifted from the AgRaman peaks, which can be attributed to a phonon softening effect. With non-resonant excitation, no oscillations are observed and therefore a displacive excitation can be attributed to the phonon generation in Sb2S3. In addition, TAS revealed two processes that decay within 10ps. One of the processes has a lifetime that resembles the laser temporal width and can be attributed to multi-probe absorption. The other process has a lifetime that decreases with increasing pump fluence and can be attributed to the electron-incoherent phonon scattering. The large scattering processes found may also indicate a possible energy loss channel for the carriers.
These findings thus shed new light on the interesting quasi-particle and charge dynamics in this novel light harvesting system. |
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Sum Tze Chien |
author_facet |
Sum Tze Chien Chong, Wee Kiang. |
format |
Final Year Project |
author |
Chong, Wee Kiang. |
author_sort |
Chong, Wee Kiang. |
title |
Coherent phonon and charge dynamics in antimony sulfide. |
title_short |
Coherent phonon and charge dynamics in antimony sulfide. |
title_full |
Coherent phonon and charge dynamics in antimony sulfide. |
title_fullStr |
Coherent phonon and charge dynamics in antimony sulfide. |
title_full_unstemmed |
Coherent phonon and charge dynamics in antimony sulfide. |
title_sort |
coherent phonon and charge dynamics in antimony sulfide. |
publishDate |
2013 |
url |
http://hdl.handle.net/10356/53666 |
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1759853490825330688 |